A&I XHT 15", 5/8" Mower Blade (Set of 6) - B1FE1044,6 Replacement XHT Lawnmower blade. XHT(Xtreme Hardness & Toughness) blades are 25-40% harder than standard lawnmower blades. Benefits of the HXT blade are sharper and longer lasting cutting edges. More resistance to bending. Tighter tolerances in the aftermarket vs. OEM. XHT blades also offer greater impact toughness. (3) blades for 44" cut. Fits IS500Z and IS1500Z. Center Hole 5/8" Length 15" Thickness .250 Type Medium Lift Width 2-1/2" Crossed From: 5061827 FERRIS This is an aftermarket product, not an OEM. A physical address must be provided, NO P.O. BOXES. Thanks for looking!